|
PureBytes Links
Trading Reference Links
|
Native script would be straight array processing
Loops which work on bar by bar are not native
--
Cheers
Graham Kav
AFL Writing Service
http://www.aflwriting.com
2008/6/5 sidhartha70 <sidhartha70@xxxxxxxxx>:
> Steve,
>
> Thanks for your response. Very helpful.
> I have seen the term 'Quick AFL' banded around and never really known
> what it was... So is there a way to turn Quick AFL on/off...? Or is
> SetBarsRequired() THE way to do so...??
>
> To give a little more info... I only notice the bar on which the cross
> occurs change when it's at the LEFT most edge of the window. i.e. it's
> just about to go out of view... to me that is no coincidence and does
> point the finger at it not having enough bars perhaps to calculate
> correctly. Maybe.
>
> If I run a check on the code without SetBarsRequired() defined it says
> it requires 35 bars to calc correctly. However, if I
> SetBarsRequired(50,0) of course the check now says it needs 55 bars...
> and if I replot the indicator then I no longer see the problem on the
> LHS of the screen.
>
> I think that's pretty conclusive that this is the problem.
>
> Steve, as an aside... what is defined as 'script'...?? Do for..next
> loops (which are now natively supported in AFL) count as script...?
>
> If so, I guess one has to be careful when using for...next loops of
> any kind...??
>
> Thanks for your help.
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Steve Dugas" <sjdugas@xxx> wrote:
>>
>> Hi - Probably best to start at the beginning. TJ invented QuickAFL
> to reduce
>> the time it takes charting code to execute. It is turned on by
> default in
>> charting ( AA does not currently use it ). It works by creating smaller
>> arrays from your full arrays and operating on them instead. The smaller
>> arrays consist of the bars you can see plus some number of bars
> immediately
>> preceding them which are used to "initialize" the arrays so correct
> values
>> are achieved by the time they reach the first visible bar. But certain
>> applications/formulas need to use more bars so TJ provided
> SetBarsRequired()
>> so you can specify more bars if you need to. As a practical matter,
> I think
>> most people use it to just "shut off" QuickAFL by using numbers
> larger than
>> the size of their entire array, then AB will just use all bars. So
> yes it
>> will slow down code execution as it defeats the purpose that
> QuickAFL was
>> invented for.
>>
>> Re crosses changing bars, I don't think that should happen, I would
> guess it
>> probably means you are not using enough bars. Tough to know what is
>> happening without your code, and not sure I would know what is
> happening
>> behind the scene even if I did have it. You could try playing around
> with
>> different values to see what happens...
>>
>> Steve
>>
>> ----- Original Message -----
>> From: "sidhartha70" <sidhartha70@xxx>
>> To: <amibroker@xxxxxxxxxxxxxxx>
>> Sent: Wednesday, June 04, 2008 2:10 PM
>> Subject: [amibroker] SetBarsRequired()...?
>>
>>
>> > Hi All,
>> >
>> > I'm a little confused about the use of SetBarsRquired()... How do I
>> > know specifically when I need to use it...? And How do I know how many
>> > bars to specify IF I do need to use it...??
>> >
>> > Also, doesn't it really very significantly slow code execution
>> > down...? From my experimentation, it seems to.
>> >
>> > I currently have some indicators plotting (e.g. fast and slow lines
>> > crossing) and the exact bar on which a cross occurs seems to move as I
>> > scroll backwards and forwards along a chart....
>> >
>> > Any ideas...?
>> >
>> >
>> > ------------------------------------
>> >
>> > Please note that this group is for discussion between users only.
>> >
>> > To get support from AmiBroker please send an e-mail directly to
>> > SUPPORT {at} amibroker.com
>> >
>> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> > http://www.amibroker.com/devlog/
>> >
>> > For other support material please check also:
>> > http://www.amibroker.com/support.html
>> > Yahoo! Groups Links
>> >
>> >
>> >
>> >
>>
>
>
>
> ------------------------------------
>
> Please note that this group is for discussion between users only.
>
> To get support from AmiBroker please send an e-mail directly to
> SUPPORT {at} amibroker.com
>
> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> http://www.amibroker.com/devlog/
>
> For other support material please check also:
> http://www.amibroker.com/support.html
> Yahoo! Groups Links
>
>
>
>
------------------------------------
Please note that this group is for discussion between users only.
To get support from AmiBroker please send an e-mail directly to
SUPPORT {at} amibroker.com
For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
http://www.amibroker.com/devlog/
For other support material please check also:
http://www.amibroker.com/support.html
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/amibroker/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/amibroker/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:amibroker-digest@xxxxxxxxxxxxxxx
mailto:amibroker-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
amibroker-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|